Question

when all carriers are saturated, the transport of the molecule levels off at a rate called what?

transport threshold

transport maximum

transport minimum

transport capacity

Explanation:

When carrier-mediated transport systems reach full saturation (all carrier proteins are bound to molecules), the rate of transport can no longer increase and plateaus at a defined maximum rate, which is referred to as the transport maximum. The other options do not describe this specific plateau rate: transport threshold is not a standard term for this concept, transport minimum refers to the lowest rate (not the saturated plateau), and transport capacity typically refers to the total number of carriers rather than the rate of transport.

Answer:

B. Transport maximum